Synthetic fibers are currently needed for many applications in the private and industrial spheres. For example, this applies to all types of garments, reinforcing fabrics, industrial textiles, wear pads, filters, etc. For this purpose the corresponding polymer, which is usually present in piece or in powder form, is mixed with a solvent, melted, homogenized, degassed and then fed, still in the viscous state, to nozzles, from which it is then extruded at high pressure to form the fibers.
For example, a method is known from WO2008/138597 in which liquid sulfuric acid is used as a solvent and at least the mixing, homogenization and degassing take place in a preferably continuously operated single-shaft or twin-shaft reactor. This eliminates the need for the hitherto necessary cooling of the sulfuric acid to below its coagulation point, making the entire process significantly simpler and less costly